塔式起重机臂架周期性拓扑优化设计

Periodic Topology Optimization Design of Tower Crane Boom

摘要:

为实现塔式起重机臂架桁架结构腹杆的布局优化，提出了基于连续体拓扑优化的桁架结构优化设计方法.首先去除起重臂腹杆，用腹板代替，同时为克服臂架细长难以进行拓扑优化的特点，将起重臂划分为若干个优化周期，建立臂架的周期性板梁优化模型； 然后使用周期性SKO（soft kill option）方法对腹板进行连续体拓扑优化，优化中使用温度过滤函数消除棋盘格式现象，得到优化的腹板拓扑构型；最后使用有限单元8邻域网格模型骨架提取算法得到腹板拓扑的中心骨架进而得到优化的腹杆布局.选取QTZ63塔式起重机最大幅度、最大起重量和最大应力3种典型工况作为优化工况，并考虑起升动载荷、风载荷及惯性载荷进行优化设计.基于3种典型工况，从强度、刚度、稳定性方面对原臂架和优化臂架进行了对比分析，验证了优化方法的有效性.

关键词:塔式起重机臂架; 拓扑优化; 腹杆布局; 周期性; 软杀法; 骨架提取

Abstract:

In order to achieve the layout optimization of web members of tower crane boom, a truss topology optimization method based on continuum was proposed. First, the optimization model was established by replacing web members with web plates. The web plates were divided into several subdomains so that the periodic SKO (soft kill option) method can be used for topology optimization of the slender boom. Next, element temperature filter function was added into the SKO method for the elimination of numerical instability like checkerboard. After getting the optimized topology of web plates, the skeleton extraction algorithm based on 8neighbourhood elements was employed to extract its skeleton and get optimized layout of web members. Based on three kinds of typical working conditions of QTZ63 tower crane, the optimization was conducted with consideration of hoisting dynamic load, wind load and inertial load. Finally, the optimized boom was proved to be effective by comparing with the original boom in strength, stiffness and stability under three typical working conditions.

Key words:tower crane boom; topology optimization; web layout; periodicity; soft kill option; skeleton extraction